Core controlling device for casting



Patented Mar. 19, 19 .6

2,396,778 CORE CONTROLLING DEVICE FOR CASTING Paul E. Flowers, Shaker Heights, Ohio, assignor to The Hydraulic Inc., Wilmington, ware Development Corporation, DeL, a corporation of Dela- Application April 9, 1942, Serial No. 438,347

16 Claims.

This invention relates to casting and, in particular, to means for handling cores used for die casting.

The cores used in connection with casting operations performed on die casting machines are generally of solid material and employed for the casting of an indefinite number of work pieces. To this end means have been provided which insert a core into the mold of an injection machine and hold the core in its inserted position during the injection or casting operation.

After completion of the casting operation, the core is removed from the cast article and used for another casting operation.

Since, as is well known, the cast or injected metal freezes itself to the core, considerable power is required to crack the core loose from the cast article. To have this power available, core controlling devices as heretofore known are over-dimensioned, i. e., have a plunger of unduly large diameter, thereby materially impeding the operation of the casting machine itself and the handling of the core.

It is, therefore, an object of this invention to provi e an improved core controlling device for use in connection with casting machines, which will overcome the above mentioned drawback.

It is another object of the invention to provide an improved core controlling device 'for casting machines, which is of a relatively small size but still has adequate power to withdraw the core or cores from a cast article.

Another object of the invention consists in the provision of a core controlling device which comprises means for automatically intensifying the pressure of the device when cracking the core or cores loose from the cast article, whereupon the pressure is automatically reduced to complete the withdrawal of the core from the finished article;

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

Figure 1 diagrammatically indicates a core controlling device according to the invention in connection with a die casting machine.

Figure 2 is a section through the core controlling device itself, showing the device in a position which it occupies when the core handled thereby is fully inserted in the mold.

Figure 3 is a section similar to that of Figure 2, but showing the device in a position which it occupies at the end of a withdrawal of the core from the mold.

her 24 is connected to the piston General arrangement The core controlling device according to the invention comprises substantially a main plunger with'an advancing area and a smaller retraction area, and furthermore comprises an intensifier cylinder-piston-assembly which becomes effective automatically at the initial phase of the withdrawal of a core from the mold and furnishes intensified pressure to the retraction area of the main plunger.

When the core has actually been cracked loose from the cast work piece, the intensifying action of the intensifier cylinder-piston-assembly automatically ceases and the core is withdrawn under the normal pressure acting on the retraction area of the main plunger.

Structural arrangement Referring now to the drawings in detail, the

arrangement shown in Figure 1 comprises a stationary mold half I and a movable mold half 2 pressed against the stationary mold half by a clamping ram 3. The stationary mold half I has rigidly connected thereto an injection cylinder 4 into which metal is fed through the opening 5, and from which the material is injected into the mold half I by means of the injection plunger 6.

In order to produce a casting with cavities therein, cores 7 are inserted into the mold halves l and 2 by means of core controlling devices, generally designated 8.

Figures 2 and 3, showing a section through the core controlling device, comprise a main cylinder shown in the drawing.

Reciprocably mounted in the main cylinder 9 is a main plunger, generally designated l2, and comprising a piston I3 with an advancing area It and a retraction area [5. Connected to the piston I3 is a piston rod [6 passing through the closure member H at the bottom of the main cylinder 9. The closure member I1 is connected to the main cylinder 9 in any convenient manner, for instance by screws I The piston l3 comprises a cylinder l9 extending into the piston rod l6 and having reciprocably mounted therein a piston 20. The piston 20 has connected thereto an intensifier plunger 2| passing through the bottom 22 of the cylinder l9 into an intensifier cylinder 23, which latter is provided in the lower portion of the piston rod l6 andis closed by a closure member 24. The

rod H5 in any closure memtensifier plunger 2 I.

The piston rod I6 is also provided with three inclined passageways 30, 3| and 32 adapted, at certain times, to establish fluid connection between- 29 surrounding t e 7.

the cylinder I9 and the retraction area I5. The

plunger 2I also comprises a passageway 33 leading from the advancing area I4 of the main piston I3 to the lower portion of the cylinder I9 and in cluding a check valve 34 opening in the from the lower portion of the cylinder I9 to the advancing area Id. The upper end of the cylinder w -communicates through'a, conduit 35 with the cranduitiil. The conduit 35 passes through and is slidablein a closure member 35 threaded into 4 the main piston I3. The outer diameter of the conduit 35 is less than the diameter of the recess am the piston 20 so that fluid from the recess 2n may pass into the upper portion of the cylinder l9 even when the conduit extends into the recess 20a.

r Operation It maybe assumed that the mold halves I and 2 have been closed and that a core is to be inserted into the mold halves I and 2. It may 'further be assumed that the core controlling device occupies the position shown in Figure 3 with the exception that the piston 20 is in its upper position in which the spring 29 is expanded. To insert thecore I into the mold halves l and 2, the operator connects the pipe line I I with apressure fluid source and the pipe line I0 with an exhaust. Fluid pressure then passes through pipe line H and acts upon the advancing area I4 of the main piston I3 so as to move the main plunger I2 downwardly. The fluid expelled lfrom the lower portion of the main cylinde'r 9,"during the downward movement of the main plunger I2, passes through the passageway 3I,=the lower portion of the cylinder I 8, the passageway 33and check valve 34 into the upper portion'of the main cylinder 9, where it likewise acts upon the advancing area I4 of thepisto'n I3.

When the core I has 7 sired extent, it engages an abutment and the main plunger I2 comes to a halt. The core controlling device then occupies the position of Figure 2 in which-the passageway 3I has just been closed by direction creased pressure in the cylinder 23, which pressure is conveyed through the passageway 2! to the retraction area I5, thereby initiating the retraction stroke of the main plunger I2, rod 26 and core I connected thereto. In other words, an increased or intensified pressure acts upon the retraction area of the main plunger I2 for cracking the core I loose from the cast article.

Fluid pressure expelled from the lower portion of the piston I9, during the downward movement ZQI the piston 20, passes through the passageway 33 andcheck valve 34 into the upper portion of the main cylinder 9 from where it escapes through the pipe line I I.

When "the piston 23 has moved downwardly to -such an extent that it releases the passageway cycle of the plunger been advanced to the dethe closure member IT. The main'plunger I2 is then held under a predetermined pressure while the injection plunger is advanced to perform the injection operation. I

When the casting operation has been completed and it is desire'dto withdraw the core I irom the cas't article, the operatorreverses the connection of the fluid source and exhaust with the pipe lines II. and I0 so thatnow. pressure fluid is admitted through the pipe line lmwhile' fluid is exhausted through pipeline .I I; ilnfthis'wa'y pressure fluid enters: the recess 2am and the upper .portioni of the cylinder I91: As soon' as pressure buildsaup-in the upper portion of the tram thereiflows into cylinder I9, the piston 20 moves downwardly" against the thrust intensifier 'plungerZI moves; toward the closure member 24 for. the; cylindersr23z, This Tea-uses? y mi,

ofthe spring 29 so that the "whatI'claim as new and 2 main plunger reciprocable in sa ing area 32, the core I has actually been cracked loose from the cast article, and now pressure fluid conveyed through conduits I0 and 35 will flow from theupperportion of the cylinder I 9 through the passageway 32 directly to the retraction area I5 and complete the retraction" or withdrawal of the core flOm the mold halves i and 2 at a reduced. pressure while the intensifier is V ineffective. When the core I is fully withdrawn, the core controlling device occupies the position shown in Figure 3. In this position the spring 29 is compressedand stays compressed as long as pressureprevails in the upper portion of the cylinder I9.

' Asjsoon as, for the initiation of a new working I2, the conduit I0 is con nected with an exhaust and the conduit i I with a pressure fluid source, the spring 29 pushes the. piston 20 upwardly and the space beneath the" piston 20 is filled byfluid passing from the lower portion of the cylinder 9 through the inclined passageway an into the lower portion ,of'thec'ylinder I9, while fluid, also passes from the lower portion of the cylinder 9 through the passageway 21 into the cylinder 23. o

It will be understood that'I desire to comprehend within my. invention such modificationsas come within the scope of the claims and'the invention. r c

Having thus fully j described my invention,

desire to secure by LettersBatentis: V V ,o I I 1." In combination, a'main' cylinder, a hollow main plunger reciprocable in said cylinder'and having an advancing area and a retraction area, an intensifier plunger 'reciprocable in said main plunger for exerting intensified fluid pressurelori one ofsaid areas to moves'aidjmain plunger, means for conveying fluidpressurejto. 'said'iri'- tensifier plungerfpr moving the same" in said main plunger, and meansresponsive to a predej-j' termined -movement of said intensifier plunger; simultaneously to interruptvthe intensiiyingacj tionof the latter to'permit the further supply of. fluid" pressure to said one area to continue the movement of said m in'pmnger;

2'. In combination, a' 'main cylinder, a hollow d main cylinder and having an advancingrareaand a retraction area; can intensifier recipro'cahle f. in said. main plunger and having an; advancing vareapforail-= vancing said intensifier and an intensifying area one of said areas to move said main plunger, means for supplying pressure fluid to the advanc of said intensifier for actuating the same, and means responsive t'oa predetermined movement of said'inte'nsifier for'dir'ectly matey.- in'gpressure fluid irogptheiadva'hcing area'ofi sa'i intensifier'tosaid one area of said main plii'rfg in said main cylinder, means for meat i 3. combination, a "main cylinder, 'a hollow main "plunger reciprocable "in "said cylinder and having associated *therewith fluid operable advancing 4 and "retracting means for reciprocating said plunger, an intensifier reciprocable in said main plunger, fluid "operable means associated with said intensifier for advancing"saidiintensifier independently of said-main plunger, "means responsive to an advancing movement -of'said intensifier for creating increased:fluidpressure and conveying 1 the same to. said retracting'means for actuating'said plunger, and means controlled by said intensifier and adapted in response to a predetermined travel of said "intensifier "during the advancing movement of the latter :to establish fluid "connection between said fluid operable means and said retracting means for subjecting saiidretractingmeans to are'ducedpressure.

4. In combination, "a main cylinder, a hollow mainplunger having an advancing area and a retraction area anintensifier"reciprocable in said main plungerand having a-main area and'an'intensifying area, means 'for supplyingpressure fluid to said main area to advance said intensifier, means responsive to the advancement of said intensifier for creating an intensified fluid pressure-means for conveying the same from said intensifying area to one of said areas of said mainplunger for actuating the same, and means responsive to a predetermined advancement .of said intensifier for establishing direct fluid communication between-saidmain areaand said one area of 'saidmain plunger.

5.In combination, a main cylinder, a hollow main plunger reciprocable in said main cylinder and having an advancing area and a retraction area, an intensifier reciprocable in said 'main plunger and having a main area for advancing said intensifierarea for creating an intensified fluid pressure on said retraction area'to thereby retract said main -plunger, means for conveying pressure-fluid from saidintensifying area to said retraction area; and means responsive to a pre- 6. In combination, a main cylinder, a hollow main plunger having an advancing area and a retraction area, an intensifier having a main area for advancing said intensifier and an intensifying area for supplying fiuid at an intensified pressure to said retraction area, conduit means continuousl establishing fluid connection between said intensifying area and said retraction area, and means controlled by said intensifier and responsive to a predetermined movement of the latter for establishing direct fluid connection between said main area and said 7. In combination, a main cylinder, a hollow main plunger having an advancing area and a retraction area and being reciprocable in said main cylinder, a first auxiliary cylinder in said main plunger, a second auxiliary cylinder in said main plunger, an auxiliary plunger reciprocable supplying pressure fluid to said first auxiliary cylinder to actuate said main plunger, an intensifier connected to said auxiliary plunger and operable thereby to create intensified pressure in said second auxiliary cylinder, means for conveying fluid from said second auxiliar cylinder to said retraction area to initiate a retraction stroke of said main plunger, and means responsive to a predetermined relative movement of said auxiliar plunger and said main plunger for establishing direct 3 fluid :connection betweenrsaid .ffirst auxiliary cylinder and said retraction ,area to continuemovement of saidmain plungerfat a reduced pressure.

8. In combination, a main cylinder, a hollow main 'plungerreciprocable in said main cylinder, said main plunger having an advancing area and position. V

9. In combination, amain cylinder, a hollow main plunger reciprocable in said main cylinder, a fluid operable intensifier reciprocable in said main plunger, means for advancing said intensifier to cause the "latter to "supply lfluid at an intensified pressure tosaid main plunger to initiate movement of the latter in a predetermined diauxiliary piston with an exhaust, and third conduit means controlled by said auxiliary piston and. responsive to a predetermined advancing movement of the first conduit means.

11. ,In a core controlling device for casting machines, a reciprocable control member, a core supported by said control member, said control a withdrawal movement of said core, and means responsive to a predetermined withdrawal movement of said core for continuing the withdrawal movement of the latter while making said intensifier inefiective.

12. In a core controlling reciprocable member and movable by the latter selectively in a first direction to be inserted into a mold, or in a second direction to be withdrawn from a cast article in said mold, fluid operable intensifying means reciprocable within said reciprocable member for creating intensified pressure, means for conveying said intensified pressure to said reciprocable member to initiate movement of the latter in said second direction, and means responsive to a, predetermined withdrawal movement of said core for making said intensifying means inefiective, while causing continuation of movement of said reciprocable member at a reduced pressure in said second di- 'rection.

13. In an apparatus for releasing a device that is tightly wedged in one position during the cycle of operation thereof that includes a main cylinder, a hollow main plunger reciprocable therein and having an advancing areaand a retraction area, an intensifier plunger reciprocable within said hollow plunger and having an advancing area and an intensifying area associated therewith, conduit means continuously establishing fluid connection between said intensifying area and said retraction area, and means controlled by said intensifier responsive to a predetermined advancing movement of thellatter for establishing direct fluid connection between said intensifier advancing area and said' main plunger retraction area.

- 14. In an apparatus for reciprocating a member from one position to a second position and releasing said member from one of said positions in which it is wedged that includes, a cylinder, a hollow main plunger reciprocablewithin said cylinder and having associated therewith fluid operable advancing and retracting means for reciprocating said plunger, a, difierential plunger reciprocable in said main plunger, means for introducing fluid pressure to a larger area of said differential plunger for advancing the same independently of said main plunger, means associated with the smaller area of said differential plunger for creating a supply of fluid at increased pressure in response to the advancing movement thereof, and conduit means for conveying said increased pressure to said retracting means for actuating said plunger.

15. In an apparatus for reciprocating a member from one position to a second position and releasing said member from one of said positions in which it is wedged that includes, a cylinder, a hollow main plunger reciprocable within said cylinder and having associated therewith fluid operable advancing and retracting means for reciprocating said plunger, a difieren'tial plunger reciprocable in said main plunger, means for introducing fluid pressure to the larger area of said differential plunger for advancing the same independently of said main plunger, means associated with the smaller area of said differential plunger for creating a supply of fluid at increased pressure in response to the advancing movement thereof, conduit means for conveying said increased pressure to said retracting means for actuating said plunger, and means controlled by said differential plunger and adapted in response to a predetermined travel of said plunger during the advancing movement thereof to establish fluid connection between said larger area and said retracting means for actuating said retracting means at a reduced pressure.

16. In an apparatus for reciprocating a work member to and from working position and for releasing said member from said working position that include sa cylinder, a main plunger reciprocable within said cylinder and having advancing and retracting means associated therewith, said main plunger having therein a flrst cavity and acseoond cavity, a differential plunger reciprocable in said cavities and having the larger portion thereof disposed in said first cavity'and the smaller portion thereof disposed in said sec- 7 0nd cavity, conduit means for introducing pres-- sure fluid into said first cavity for advancing said difierential plunger whereby to create an increased or intensified pressure in said second cavity in response to the movement of said smaller portion of said plunger, conduit means interconnecting said second cavity with said main plunger retracting .means, and other conduit means adapted in response to a predetermined advancing movement of said difierential plunger to connect said retracting means with said first cavity.

PAUL E. FLOWERS. 

